Respiratory Conditions: Asthma, Pneumonia, and Tuberculosis Summary

Respiratory Conditions: Key Summaries

Bronchial Asthma

Reversible airway hyperresponsiveness.

Atopic Triad

• Asthma
• Rhinitis
• Dermatitis

Mechanism: IgE mediated, involving eosinophils (leading to bronchospasm, mucus, and edema).

Chronic Changes: Fibrosis and smooth muscle hypertrophy.

Clinical Presentation

• Wheeze
• Dyspnea
• Cough
• Chest tightness

Diagnosis

• FEV1 < 80%
• FEV1/FVC < 80%
• Reversibility test > 12%

Acute Severe Features

Arrhythmia, cyanosis, hypoxia, silent chest.

Treatment

1. SABA (Salbutamol)
2. Low ICS (Fluticasone)
3. ICS + LABA (Formoterol)

Acute Management

Oxygen, nebulized SABA, Ipratropium, systemic corticosteroids, IV magnesium sulfate. Mechanical ventilation if severe.

Pneumonias (12-16)

Community Acquired Pneumonia (CAP) Pathogens

Streptococcus pneumoniae, H. influenzae, Legionella, Moraxella, Mycoplasma pneumoniae, Chlamydiae pneumoniae.

Risk Factors: Smoking, influenza, bites, and IV drug use.

Hospital Acquired Pneumonia (HAP) Pathogens (> 48h)

Pseudomonas, Klebsiella, E. coli.

Risk Factors: Intubation, aspiration, reduced immunity.

Immunocompromised Pathogens

H. influenzae, Aspergillus, Pneumocystis jirovecii.

Risk Factors: Neutropenia, HIV, splenectomy.

Typical vs. Atypical Pneumonia

• Typical: Strep. pneumoniae, Haemophilus, Staph aureus, Moraxella. Symptoms: High fever, consolidation in alveoli, purulent cough, high neutrophils.
• Atypical: Mycoplasma, Legionella, Chlamydia. Symptoms: Low fever, dry cough, mild WBC count.

Diagnosis and Severity

Diagnosis: Chest X-ray, WBC-CRP, sputum analysis, oxygenation status.

Severity Criteria: RR>30, Diastolic BP <60 mmHg, Hypoxemia, BUN >20.

Treatment

CAP:

• Outpatient: Macrolides (Azithromycin)
• Severe: Fluoroquinolones ± Tetracyclines

HAP:

• MRSA Coverage: Vancomycin or Linezolid
• Pseudomonas Coverage: $eta$-Lactam or Fluoroquinolone

Pulmonary Tuberculosis (TB)

Forms of TB

• Primary: Often asymptomatic, affects lower lobes, characterized by caseous necrosis + hilar lymph nodes.
• Latent: Dormant inside granulomas.
• Reactivation: Symptomatic, affects upper lobes, forms cavities.
• Dissemination: Vascular spread, resulting in Miliary TB.

Clinical Features

Fever, weight loss, hemoptysis, cough.

Diagnosis

• PPD Skin Test (Exposure indicator)
• Active TB: Acid Fast Bacilli Culture (Gold Standard) + Chest X-ray.

Treatment Regimens

Isolation until sputum AFB is negative.

Active TB:

• Initial Phase (2 Months): Isoniazid + Rifampicin + Pyrazinamide ± Ethambutol
• Continuation Phase (4 Months): Isoniazid + Rifampicin

Latent TB: 9 months of Isoniazid.